1. Field of the Invention
The present invention is generally related to an adhesive bookbinder and in particular to a case-in device of the adhesive bookbinder which provides a correct and precise operation of adhesively adding a cover to a book body.
2. The Related Art
Adhesive bookbinders have been widely used to bind books, such as magazines, text books, notebooks. As shown in FIG. 2 of the attached drawings, the general procedure of binding books with an adhesive bookbinder is holding the plurality of sheets that constitute the book body (step 10'), cutting the sheets (step 11'), applying adhesive to the book body (step 12') and then adding a cover to the book body by placing the cover on the book body and applying a force thereto to have the cover adhesively secured to the book body (step 13').
Thus, a conventional adhesive bookbinder comprises holding means 10 for holding the book body, cutting means 11 for cutting the sheets, adhesive applying means 12 for applying the adhesive to the book body and cover adding means 13 for adding and securing the book cover to the book body, as is schematically shown in FIG. 1. A case-in device may be incorporated in the adhesive bookbinder to perform some of these operations and a conventional case-in device of adhesive bookbinder is shown in FIGS. 3 and 4 of the attached drawings and labelled with reference numeral 20.
As shown in FIGS. 3 and 4, the conventional case-in device 20 generally comprises a binding platform 21 and two support plates 22 and 23 fixed thereto to be spaced from each other to define therebetween a space for accommodating a driving motor 24 which is fixed to the plate 23 and two transmission shafts 28 and 29 rotatably supported between the support plates 22 and 23. A gear train 25 is arranged between the motor 24 and the two shafts 28 and 29, comprising a motor output pinion fixed to the motor spindle and two gears 26 and 27, to which the shafts 28 and 29 are respectively fixed, engaging the motor output pinion and thus driven by the motor in such a way to rotate in opposite directions. Each of the shafts 28 and 29 also has a further gear 31 or 30 fixed thereon so that the gears 31 and 30 are rotatable in opposite directions.
The binding platform 21 has two pairs of elongated slots 32 to respectively correspond to two clamping plates 33 and 34 (FIG. 4). Each of the clamping plates 33 and 34 is connected to two racks 35 via slide blocks that are movably received within and guided by the slots 32. The racks 35 are respectively engaged by the gears 26, 27, 30 and 31 so that when the motor 24 is actuated, the clamping plates 33 and 34 are driven to move relative to each other in opposite directions so as to apply force to a book and a book cover position between the clamping plates 33 and 34. A spring 36 is connected between each of the racks 35 and the binding platform 21 for biasing purpose.
Such a conventional structure of the case-in device has several drawbacks. For example, the movement of the clamping plates is caused by the engagement between the racks and the gears and is completely guided by the contact engagement between the slide blocks within the slots. Since there are always plays or backlashes between the racks and the gears, the movements of the clamping plate may become un-smooth after a long term service of the device. Further, the tolerance between the slide blocks and the slots may be getting greater with the use of the device which may finally causes undesired mechanical interference therebetween so as to result in poor control of the movement of the clamping plates. This eventually causes a quality problem in binding books.
Thus, it is desirable to have a case-in device of the adhesive bookbinder which eliminates/overcomes the problems or drawbacks encountered in the prior art.